--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hooks/logstats.py	Wed Apr 22 11:00:50 2015 +0200
@@ -0,0 +1,59 @@
+# copyright 2014 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
+
+"""looping task for dumping instance's stats in a file
+"""
+
+__docformat__ = "restructuredtext en"
+
+from datetime import datetime
+import json
+
+from cubicweb.server import hook
+
+class LogStatsStartHook(hook.Hook):
+    """register task to regularly dump instance's stats in a file
+
+    data are stored as one json entry per row
+    """
+    __regid__ = 'cubicweb.hook.logstats.start'
+    events = ('server_startup',)
+
+    def __call__(self):
+        interval = self.repo.config.get('logstat-interval', 0)
+        if interval <= 0:
+            return            
+
+        def dump_stats(repo):
+            statsfile = repo.config.get('logstat-file')
+            with repo.internal_cnx() as cnx:
+                stats = cnx.call_service('repo_stats')
+                gcstats = cnx.call_service('repo_gc_stats', nmax=5)
+                
+            allstats = {'resources': stats,
+                        'memory': gcstats,
+                        'timestamp': datetime.utcnow().isoformat(),
+                       }
+            try:
+                with open(statsfile, 'ab') as ofile:
+                    json.dump(allstats, ofile)
+                    ofile.write('\n')
+            except IOError:
+                repo.warning('Cannot open stats file for writing: %s', statsfile)
+                    
+        self.repo.looping_task(interval, dump_stats, self.repo)